It is increasingly common for a file to be generated and then shared with multiple users. This is especially true in the corporate, government, and academic realms; however, there also exists a need to restrict access to these files. In other words, there is a need to prevent unauthorized users from viewing the files.
There have been attempts in the past to prevent unauthorized users from viewing the files; however, most of these attempts rely on encryption using a password. This can be frustrating to an authorized user trying to view the file because the authorized user must remember the password and deal with prompts for the password. Regardless, users still desire the ability to share files and prevent unauthorized users from viewing the files.